Method of improving paper machine operation



Patented June 2, 193 1 Qum'ra new "ms Arau'r orricE HAROLD ROBERT RAFTON, OF LAWRENCE, MASSACHUSETTS, ASSIGNOR" T RAFFOLD PROCESS CORPORaATION, A QORPORATION MASSACHUSETTS mnrnon or IMPROVING PAPER MACHINE ornnA'rIoN No Drawing. Application filed December 11, 1928, Serial No. 325,408. Rgnewed March 5, .1931. i i

This inventionrelates to the manufacture of paper and more particularly to the manufactureof paper filled with alkaline filler.

soft lum fIhe principal object of my invention is to provide a method for paper manufacture whereby alkaline filler furnishes may be run on the paper machine substantially free from soft lumps. I

An important object of my invention is to provide a method whereby both alkaline filler and casein may be used in the same furnish substantially without difiiculty from formation. A furt er object of my invention is to produce paper containing both casein and alkaline filler, which is substantially. free from lumps and lump spots. p

Other objects and advantages of my invention will become apparent during the course of the following description.

In the manufacture of substantially unsized paper filled with alkaline filler, particularly when old paper stock is one of the fibrous constituents, soft lumps form in the furnish and cause br eaks on the paper machine. I have found that this formation of lumps istraceable to the presence in the furnish of casein from coated broke, and that the trouble from soft lumps may be substantially eliminated in the manufacture of paper filled with alkaline filler by substantially exeluding casein from the furnish. However this exclusion'is not always feasible or de-- sirable.

In my copending application Serial No. 325,407, filed December 11, 1928, I disclose a method whereby the manufacture of paper filled with alkaline filler may be carried on substantially free from soft lumps or at least with only a commercially unimportant number of soft lumps even in-the presen'ce of casein in the furnish. It is to be noted that the casein which is present finds its way into the furnish from the coated broke (this term including the coatedpaper present in clippings, trimmings, or the like) in-the furnish, or from the old paper stock made from old' papers possessing some casein bearings constituents, or from circulating mill waters which in. turn originally derive their casein filed November 24, 1928. It consists substantially in adding alkaline filler, preferably c0ntinuously, preferably in suspension, at the wet end of the paper machine to a mix ineluding fibrous material, casein, and alum, and sizing materials if such are to be used.

In the preferred practice of nay-invention I add to the beater or other similar machine all fibrous materials to be used, with the exception of those fibrous materials coming September 5,1928, and Serial Nos. 321,753 and 321,754, both under the definition of alkaline filler herein- ,a-fter set forth and such fibrous material as is present in the stock recovered from the white water. The casein bearing constituent which is normally apart of the fibrous furnish is also added in the beater. I may also add to the beater alum, or rosin size and alum, or sodium silicate and. alum, or both rosin size and sodium silicate and alum. In any event, I prefer to have an excess of alum present; Filler other than alkaline fillermay be added if desired as well as coloring matter or the like.

After the usual treatment in the beater, the

mix ispreferably-passed through the beater chest, joi'dan, and'machine chest in the customary' manner. 1 This procedure and/or order of steps is not essential, and may vary consid- .erably' as. will be apparent to one skilled in the art. The mix, still inrelatively cgncentrated form, is now at the point where it is read for dilution preparatory to delive to the deb-forming end of the paper machine.

All water usedfor dilution up to this point in the process is preferably either fresh water,

. or white water which has been purified so that'it contains only anegligible amount of alkaline filler. However, at this point, untreated white water as obtained from the paper machine may be used as diluting water. During dilution at this point, or subsequent thereto, the alkaline filler preferably in aqueous suspension is added preferably continuously, due care being taken that adequate mixing is insured.

According to the definition of alkaline filler hereinafter set forth, this term includes fibrous matter in combination with the mineral alkaline filler itself. In such cases the fibrous material must be properly broken down in a suitable apparatus before addition, as will be apparent. It may be refined separately if desired, but ordinarily this will be unnecessary as such fibres have already been possible after the production of the white water and such stock should preferably be returned promptly to its point of re-use so as to afiord as little time as possible for contact between the alkaline filler and the constituents of the mix which have accompanied it in the white water.

If the recovered stock be obtained from a settling system, a convenient way is to add the recovered stock directly from this settling system continuously at the mixing box at the point of dilution of the stock. If the stock is recovered by a filter or deckering system by mixing the white water with relatively concentrated stock as a sweetener, then a convenient method is to divert part or all of the stream of concentrated fibrous stock just before its delivery to the mixing box, and utilize this as sweetener stock, delivering it after it has so functioned to the mixing box.

' {In this way the stock containing the alkaline filler derived from the white water remains for only a brief interval in concentrated con- ]dition, and is quickly diluted at the mixing Where casein containing constituents are to be used, in order to prevent soft lumps the alkaline filler must be added as stated above at or subsequent to the point where the stock is in dilute condition; if it be added prior to this point, it results in the production of soft lumps in the mix. In order to have my method effective, the alkaline filler must be added at a-point where there is a minimum of intimacy and time of contact of the alkaline filler with the constituents of the mix. The

intimacy of contact is particularly damaging at high concentrations, particularly when accompanied by agitation. When the intimacy and time of contact are reduced to a minimum, as they are at the wet end of the paper machine, the tendency for the alkaline filler 'in conjunction with the casein bearing constituent to form soft lumps is greatly reduced if not entirely eliminated.

An illustrative furnish which may he satisfactorily used in carrying out my inventidn is as follows:

, Materials aaezea in beater Fibrous furnish, e. sulphite pulp and soda pulp, equal parts (air dry weight) 1400 Casein containing ingredient (air dry weight), e. g. coated broke 300 Alum 40 Material added proportionately and continuously on dilution Pounds Pounds Alkaline filler (bone dry weight), e. g. calcium carbonate magnesium hydroxide 300 Fibrous furnish, e. g. sulphite pulp, soda pulp, and old paper stock,

equal parts (air dry weight) 1400.

Casein containing ingredient (air dry weights) e. g. coated brokeL- 300 Rosin size 6 Alum M aterz'aladded proportionately and continuously on dilution P d Alkaline filler v (bone dry weight), e. g. calcium carbonate magneslum hydroxide 300 Another furnish which may be used is: Materials added in beater Pounds Material added proportionately and centimeouslg on dz'dutian Alkaline filler (bone dry weight) e. g. calcium carbonate magnesium hydroxide Pounds The furnishes given above are to be con-- sidered as illustrative only and not limiting,

as I have found thatI may carry on my invention with a Wide variety of materials used in widely varying quantities and still obtain satisfactory results.

It will be noted in the second illustrative furnish. given above, that the rosin size is present in an amount of six pounds in a total furnish of approximately 2000 lbs, or approximately only three-tenths of one per cent on the total furnish. As is apparent, this is an amount of size insufficient to impart a substantial degree of sizing to the pa- .per. Its use in that furnish is thus obviously not from the standpoint of sizing the sheet, but rather for the purpose, well known in the art, of imparting better running qualities to the stock on the paper machine.

The papers made by my process may be finished as usual as by machine calenderin-g or supercalendering ifdesired, and if sized, may be used for conversion, e. g, for coating.

My method is particularly valuable as it permits the operation of a mill manufacturing both coated paper and alkaline filled paper without the segregation of the coated broke into furnishes which do not containalkaline filler. It also does away substan tially with the difiiculties and necessity of and that the capacity of the beater for fibrous material, and its beating efi'iciency, are enhanced by the absence of the major part of the filler from the beater. Furthermore the material recovered from the white water which of course contains alkaline filler may thereby be delivered to the beater or at any other point where the stock is still in concentrated condition, such as for instance in any of the stuff chests. This procedure permits the. utilization of. the equipment commonly used for white water recovery with the normally employed piping connections, instead [of the changed piping required when only the alkaline filler is added at the wet end of thepaper machine. 'Where the recovery system is of the filtering or deckering type, the

' sweetener stock may be taken exactly as is customary from one of the stuff chests, and

this stock together with the recovered inaterial from the white water may be returned therto or elsewhere in the concentrated stock system as desired. A method similar to this method is broadly claimed in my copending application Serial No. 321,754, filed Novemher 24, 1928, but the specific use of that meth od when casein is employed in the furnish, or the advantages inherent thereto, namely, the substantial elimination of soft lumps, is not therein disclosed.

In the place of alum, I may use with a measure of success certain acidic materials such as sulphuric acid (H 80 or acid salts such as sodium bisulphate (NaHSO or metallic salts such as zinc sulphate, or other salts of aluminum such as the chloride or the like. Because of economy, however, I prefer to use ordinary alum;

In place of rosin size I may use other sizes, such as soaps, for example the oleates, or-any other material derived by treatment with an alkaline substance or the like from material originally of acid characteristics or from material which likewise is of a partly or completely saponifiable nature such for example as saponified beeswax. I may also use other sizing materials such as paraflin emulsions, I for example as set forth in my copending applications, Serial Nos. 304,170,. 304,173,

304,176 and 304,177, all filed September 5,

Where I use the term alkaline filler, I mean substantially water insoluble filler which when agitated in contact with freshly boiled distilled water, say for an hour, will impart a pH value to such water greater than 7.0 that is, which will be on the alkaline side of the neutral point. Among the fillers included in this group may be mentioned calcium carbonate, of which lime mud from the causticizing process is one form; calcium carbonate magnesium basic carbonate employed in the paper disclosed in my U. S.,

,atent No. 1,595,416, issued August 10, 1926; calcium carbonate magnesium hydroxide disclosed inmy U. S. Patent No. 1,415,391, issued May 9, 1922; and other substantially water insoluble normal or basic carbonates of alkaline earth metals (which expression is herein'intended to include magnesium), or compounds, double salts, or physically associated mixtures of these with one or more other acid soluble materials of a substantially water insoluble nature.

By the term alkaline filler I also intend to include fibrous material and/or other ma terial such as paper coating constituents or the like containing one or more compounds of the character referred to, such as old paers or similar a ers broke or the like.

When I use the word paper herein, I use it in the broad sense to include products of manufacture of all types and ofall weights and thicknesses, which contain as an essential constituent a considerable amount of pre- '2 pared fibre and which are capable of being produced on a Fourdrinier, cylinder, or other forming, felting, shaping or molding machine.

By the term wet end of the paper machine I intend tofinclude those instrumentalities employed in paper manufacture by which and/or in which a relatively. concentrated paper mix is diluted, and treated,- conveyed or fed up to the point of web-formation such as the mixing box, regulating and proportioning devices, rifliers, troughs, screens, head boxes, inlets, and the like, including also in-' strumentalities used in the whitewater cycle.

Where I use the expression soft lumps I meanlumps which have their origin subsequent to the screening of the stock, being form-ed in the head box, inlet or the like. These lumps are entirely different, and easily distinguishable by practical paper makers,

from slime, i. e. masses of stock usually fermerited or decomposed which settle or form on chest and pipe surfaces, and when dislodged workthrough the screens and on to the wire. Of course, slime also forms in the head box and inlets after the machine has run for a relatively long period of time without 1 wash-up, but the soft lumps I describe are entirely distinct therefrom and form, and start to give trouble, even within as short a time as several hours after the head box and inlet have been thoroughly cleaned.

Where I use the word casein herein, I use 1t 1n the genenc sense to include casein and or terial, casein bearing constituent, and alum,

alkaline filler under conditions favoring the minimizing of time of contact of the constituents of the mix, and thereafter making paper therefrom.

2. The -method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and alum, alkaline filler under conditions favoring the minimizing of intimacy and time of contact of the constituents of the mix, and thereafter making paper therefrom.

3. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and alum, alkaline filler at the wet end ofthe paper iinachine, and thereafter making paper thererom.

4'. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprislng fibrous material, casein bearing constituent, and a salt of aluminum, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom. K

. 5. The method of manufacturing paper filled with alkaline filler and containing case- *in in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and a metallic-salt, alkaline filler at the wet end of the paper machine, and there'aftermak'mg paper" therefrom. 6.. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and acidic material, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom.

7. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material including old paper stock, casein hearing constituent, and alum, alkaline filler at the wet 'end of the paper machine, and thereafter making paper therefrom.

8. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material including sulphite pulp and soda pulp and old paper stock, casein bearing constituent, and alum, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom.

9. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent comprising coated broke, and alum, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom. L

10. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a.

fibrous mix originally comprising fibrous material including old paper stock, casein bearing constituent comprising coated broke, and alum, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom.

11. The method of manufacturing paper filled with alkaline filler and containing case in in its furnish, comprisingadding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and alum,

alkaline filler comprising alkaline earth metal 3 compoundat the-wet end of the paper ma- 13. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrousmix originally comprising fibrous material, casein bearing constituent, and alum, alkaline filler comprising calcium carbonate and magnesium compound at the wet end' of the paper machine, and thereafter making paper therefrom." 1

14. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to afibrous mix originally comprising fibrous material, casein bearing constituent, andalum,

alkaline filler comprising calcium carbonate magnesium hydroxide at the wet end of the '23. The methodof manufacturing paper filled with alkaline filler and containing casepaper machine, and thereafter making paper therefrom.

15. The method of manufacturing paper filled with alkaline filler and containing case-- in in its furnish, comprising adding to a fi-" brous mix originally comprising fibrous material, casein bearing constituent, and sizing, alkaline filler at the wet end of the paper machine, and thereafter making paper'therefrom.

16. The method of'manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix originally comprising fibrous material, casein bearing constituent, and size recipitated by an excess of alum, alkaline filler at the wet end of the paper machine, and thereafter making paper therefrom.

17 The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fi-m brous mix originally comprising fibrous material, casein bearing constituent, and size in an amount insufficient to produce a substantial degree of sizing in the paper precipitated by an excess of alum, akaline filler at 'thewet end of the p per machine, and thereturing paper filled with alkaline filler and.

after making paper therefrom.

18. That step in. the method of manufaccontaining casein in its furnish comprising adding alkaline filler to the paper mix at the wet end of the paper machine.

19. The method of manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix comprising fibrous material and casein bearing constituent, alkaline filler and (acidic material at the wet end of the paper Ifn achine, and thereafter making paper there om. 20. The method of manufacturing paper filled with alkaline filler andcontaining casein in its furnish, comprising adding to a fibrous mix comprising fibrous material and casein bearing constituent, alkaline filler and a metallic salt at the Wet end of the paper machine, and thereaftermaking-paper therefrom. v

.21. The method of manufacturing paper filledLwith alkaline filler. and containing casein in its' furnish, comprising adding to a fibrous mix comprisingfibrous material and casein bearing constituent, alkaline filler and a salt of aluminum at the .wet end of the paper machine, and thereafter making paper therefrom.

22'. The method .of 'manufacturing paper filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix comprising fibrous material and casein bearing constituent, alkaline filler and alum at the wet end of the paper machine,

and thereafter making paper therefrom. n

line filler and alum at the wet end of the paper machine, and thereafter making paper therefrom. I

25. The method of manufacturing'paper :filled with alkaline filler and containing casein in its furnish, comprising adding to a fibrous mix comprising fibrous material, casein a bearing constituent, and size in an amount insuflicient' to impart a substantial degree of sizing to the paper, alkaline filler and alum at the wet end of the paper machine, and thereafter making paper therefrom.

, 26. That step in the method of manufacturing paper filled with alkaline filler and containing casein in its furnish comprising adding alkaline filler and alum to the paper mix at the wet end of the aper machine.

In testimony,whereof l aflix my signature.

HAROLD ROBERT RAFTON. 

